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111.
Md. Mahabubur Rahman Tasnim Ara Mohiuddin Ibn Shafique Md. Abdur Rahman Mohammad Lutfor Rahman 《Singapore journal of tropical geography》2023,44(3):499-518
Considering the adverse outcomes of thunderstorm-mediated lightning in recent years, this study aimed to identify the most thunderstorm-and-casualty prone regions and seasons in Bangladesh, via geospatial mapping. We attempted to forecast the number of yearly thunderstorm (TS) days for each meteorological station and district-level lightning casualties by using TS days as a proxy variable. Data on TS days and lightning casualties were collected from Bangladesh Meteorological Department and Network for Information, Response And Preparedness Activities on Disaster respectively. This study analysed 629 fatalities and 232 injuries. The Integrated Nested Laplace Approximation with Matern covariance function was employed to assess the spatial pattern of TS days. Polynomial regressions were used to forecast the number of TS days and the single clustered Generalized Estimating Equations method was employed to explore the relationship between the number of TS days and lightning casualties. The results indicated that the mean number of TS days per station increased in recent years, particularly in February, March, April, and September. We found the months of April, May, June, and September to be the most threatening months due to TS events and related casualties. The northeast region was identified as the most TS-prone region with the highest number of casualties in Bangladesh. Our analysis suggests that it might remain the most hazardous region in coming years. 相似文献
112.
Gazi Md. Nurul Islam Tai Shzee YewNik Mustapha R. Abdullah K. Kuperan Viswanathan 《Ocean & Coastal Management》2011,54(2):173-180
This paper examines the impact of Community Based Fisheries Management (CBFM) on fishing households’ welfare in Bangladesh. It analyses how the various types of livelihood assets contribute to fishers’ household incomes. The study found that fishers in CBFM project areas have improved their access to different assets including social, human, physical, financial and natural capitals. The regression results show that social capital contributed significantly to household income, indicating that social factors play very important roles in poverty alleviation in Bangladesh. Future poverty alleviation policy options need to give priority to investments in human, physical and natural capital assets. 相似文献
113.
B. S. K. REDDY K. R. KUMAR G. BALAKRISHNAIAH K. R. GOPAL R. R. REDDY V. SIVAKUMAR S. Md. ARAFATH A. P. LINGASWAMY S. PAVANKUMARI K. UMADEVI Y. N. AHAMMED 《大气科学进展》2013,30(1):235-246
Surface measurements of aerosol physical properties were made at Anantapur(14.62°N,77.65 °E,331 m a.s.l),a semiarid rural site in India,during August 2008-July 2009.Measurements included the segregated sizes of aerosolsas as well as total mass concentration and size distributions of aerosols measured at low relative humidity(RH<75%) using a Quartz Crystal Microbalance(QCM) in the 25-0.05 μm aerodynamic diameter range.The hourly average total surface aerosol mass concentration in a day varied from 15 to 70 μg m-3,with a mean value of 34.02±9.05μgm-3 for the entire study period.A clear diurnal pattern appeared in coarse,accumulation and nucleation-mode particle concentrations,with two local maxima occurring in early morning and late evening hours.The concentration of coarse-mode particles was high during the summer season,with a maximum concentration of 11.81±0.98μgm-3 in the month of April,whereas accumulationmode concentration was observed to be high in the winter period contributed >68% to the total aerosol mass concentration.Accumulation aerosol mass fraction,A f(=Ma/Mt) was highest during winter(mean value of Af~0.80) and lowest(Af~0.64) during the monsoon season.The regression analysis shows that both R eff and R m are dependent on coarse-mode aerosols.The relationship between the simultaneous measurements of daily mean aerosol optical depth at 500 nm(AOD500) and PM 2.5 mass concentration([PM2.5]) shows that surface-level aerosol mass concentration increases with the increase in columnar aerosol optical depth over the observation period. 相似文献
114.
A study on water quality of the two long-logged and abandoned headwaters in Temengor Reservoir was conducted to determine their natural recovery.In this study,we used National Water Quality Standards for Malaysia prepared by Malaysian Department of Environment as an indicator for water quality recovery.The parameters measured were dissolved oxygen(mg/L),water temperature(℃),pH,conductivity(mS/cm),total dissolved solids(mg/ L),water velocity(m/s),ortho-phosphate(PO4-P),nitrite-nitrogen(NO2-N),nitrate-nitrogen(NO3,-N)and alkalinity. In general,water quality in Sungai Enam and Sungai Telang were in ClassⅠ,indicating water quality in both streams have recovered.Based on the t-test,Sungai Enam and Sungai Telang differed significantly in all parameters except for dissolved oxygen,NO2-N and NO3-N.In spatial analyses(upper,middle and lower reaches comparisons), the two-way ANOVA analysis shows that there were significant differences in all studied parameters between the two rivers except for dissolved oxygen,total dissolved solids,NO2-N and NO3-N.Stream flow,hydrologic pathways,geomorphology,physical and environmental characteristics are essential elements in understanding the dynamics of water systems in Sungai Enam and Sungai Telang.Due to the recovery,these two headwaters are thus suitable for fish conservation and restoration sites. 相似文献
115.
116.
Acta Geotechnica - This technical paper focuses on evaluating the shear strength of unsaturated sand at drying, wetting and alternate drying–wetting cycles, as well as the correlation between... 相似文献
117.
Chowdhury Sarwar Jahan Md. Ferozur Rahaman Riad Arefin Shamser Ali Quamrul Hasan Mazumder 《Journal of the Geological Society of India》2018,91(5):613-620
Demand for irrigation water increases day by day along with meteorological vagaries and extension of irrigated area in the drought-prone Barind area of Bangladesh. This increasing stress on water resource is gradually making the area water scare. The study is aimed at studying the morphometric parameters of the Atrai-Sib river basin in the Barind area and on their relevance in water resource management based on satellite images and SRTM DEM. Computation and delineation of linear and areal aspects of the river basin and its morphometric components reveals that stream order ranges from first to eighth order showing dendritic drainage pattern. The basin represents homogeneity of soil texture; possibility of flash flood after heavy rainfall with low discharge of runoff; and is not largely affected by structural disturbance. Moderate drainage density of the river basin area indicates semipermeable soil lithology with moderate vegetation. Mean bifurcation ratio of the basin is calculated as 3.92 and elongation ratio 0.75, which indicate elongated shape of the river basin with low to moderate relief bounded in the east and west by ‘moderate to steep’ sloping land area. It reveals a flatter peak of runoff flow for longer duration and gravity flow of water. The gentle but undulating slope of the basin represents ‘excellent’ category for groundwater management as the site is favorable for infiltration due to maximum time of runoff water percolation. The east facing slopes of the basin show higher moisture content and higher vegetation than the west-facing slope. The land use pattern of the area shows that major part (95.29%) comes under the cultivated land which will support future river basin development and management. Results obtained from the study would be useful in categorization of river basins for future water resource development and management, and selection of suitable sites for water conservation structures such as check dam, percolation tank, artificial recharge of groundwater through MAR technique etc. 相似文献
118.
Mineralogy and Petrology - In the Gotsu area of the c. 200 Ma high-P/T Suo metamorphic belt in the Inner Zone of southwest Japan, blueschists occur as lenses or layers within pelitic... 相似文献
119.
Md. Mizanur Rahman Sarker Marc Van Camp Mazeda Islam Nasir Ahmed Kristine Walraevens 《Environmental Earth Sciences》2018,77(2):39
In the coastal region of Bangladesh, groundwater is mainly used for domestic and agricultural purposes, but salinization of many groundwater resources limits its suitability for human consumption and practical application. This paper reports the results of a study that has mapped the salinity distribution in different aquifer layers up to a depth of 300 m in a region bordering the Bay of Bengal based on the main hydrochemistry and has investigated the origin of the salinity using Cl/Br ratios of the samples. The subsurface consists of a sequence of deltaic sediments with an alternation of more sandy and clayey sections in which several aquifer layers can be recognized. The main hydrochemistry shows different main water types in the different aquifers, indicating varying stages of freshening or salinization processes. The most freshwater, soft NaHCO3-type water with Cl concentrations mostly below 100 mg/l, is found in the deepest aquifer at 200–300 m below ground level (b.g.l.), in which the fresh/saltwater interface is pushed far to the south. Salinity is a main problem in the shallow aquifer systems, where Cl concentrations rise to nearly 8000 mg/l and the groundwater is mostly brackish NaCl water. Investigation of the Cl/Br ratios has shown that the source of the salinity in the deep aquifer is mixing with old connate seawater and that the saline waters in the more shallow aquifers do not originate from old connate water or direct seawater intrusion, but are derived from the dissolution of evaporite salts. These must have been formed in a tidal flat under influence of a strong seasonal precipitation pattern. Long dry seasons with high evaporation rates have evaporated seawater from inundated gullies and depressions, leading to salt precipitation, while subsequent heavy monsoon rains have dissolved the formed salts, and the solution has infiltrated in the subsoil, recharging groundwater. 相似文献
120.
Water Resources - Turbulent phenomenon in braided rivers is much more complex compared to the straight and meandering rivers. The turbulent flow structure at locations upstream and downstream of... 相似文献